Optimizing trunk bus lines could improve service

Metrobus riders, especially those in the suburbs, often face long wait times between buses. With WMATA’s budget crisis, it is extremely unlikely they can add more bus service. However, there are ways WMATA could dramatically improve service at little to no cost.

Other cities, starting with Portland’s Tri-Met, have had great success with their bus networks by creating high-frequency lines. In these instances, bus riders don’t need to carry a schedule because the bus shows up too often for that to be necessary. This has the benefit of increasing convenience and mobility for riders and, consequently, ridership.

Many Metrobus routes have common segments with other bus lines, yet because they are different routes, they are often not scheduled with each other in mind. One example of this case can be seen in Metrobus routes C2, R12, and T16/17 in Greenbelt. Each of these routes serves several common points, including Greenbelt Metro, Beltway Plaza, and Greenbelt Center. There are variations in the routes, but there are also many common segments.

The C2 operates every 15-20 minutes during rush hours and every 30 minutes for most of the rest of the day. The R12 and T16/17 each operate at 30 minute headways during rush hours and hour intervals otherwise.

This could easily translate into relatively high frequencies, even off peak. With four vehicles an hour, each of the common points could see a vehicle every 15 minutes. Headways would be even better during peak periods. However, that’s not how WMATA operates these buses. During the midday period, for example, these buses depart Greenbelt Station in the direction of Greenbelt Center at 1:23 (R12), 1:24 (C2), and 1:25 (T16). The last bus, a C2, departed 29 minutes prior, and the next bus, a C2, won’t depart for 28 minutes. For passengers headed toward Greenbelt, there’s no reason that the time between the 12:54 C2 and the 1:53 C2 (59 minutes) can’t be divided into 20 minute waits with evenly spaced departures of the buses.

The above chart shows a section of a weekday. The top gray bar indicates scheduled bus departure times in the direction of Greenbelt Metro from the timepoint “Greenbelt Center”, located at the corner of Crescent Road and Gardenway. The bottom bar shows departures from Greenbelt Metro in the direction of Greenbelt Center. Notice on the lower bar that departure times on the three routes from Greenbelt Metro are clustered in roughly 3-5 minute intervals at about 25 after the hour each hour. Offsetting the T16/17 and R12 by several minutes would even out departure times, lowering average wait times for those bound for any of the common route segments.

The similar departure times for the C2, R12, and T16/17 are typical throughout the day, although during rush hours, higher frequencies help to even things up a bit. On trips toward Greenbelt Metro, it is typical for the R12 and T16/17 buses to be immediately behind one another during their entire common run through Old Greenbelt. For passengers, this situation is intolerable - to wait 30 minutes to see two buses bound for the same destination following each other. During “bunching” situations, this is upsetting. For it to be a scheduled, everyday occurrence, is completely unacceptable.

Rescheduling buses on trunk lines is one way to increase service, at least as far as the customer sees it, at very little cost to the agency. Technically, there’s no increase in capacity through rescheduling - the same number of buses, the same number of seats - but a better distribution of those seats throughout the day.

In some instances, it might make sense to reroute neighborhood buses to serve a particular trunk or to give more common segments. Simplification of route structure could increase productivity by shortening the length of routes and making it easier for riders to understand the bus line.

For instance, routing the T16/17 along the same route as the R12 between northern Greenbelt and Greenbelt Metro would decrease travel time to the Metro for Greenbelters. Extending T16/17 buses to a terminal at Beltway Plaza would maintain current service levels to the mall. It would also balance service levels between Greenbelt Center and Greenbelt Metro. Right now, the C2, with the same frequency as the combined R12/T16/17, travels via Beltway Plaza between Greenbelt Center and the Metro. The R12 makes that trip via the northern reaches of Greenbelt. The T16/17, however, travels via both before getting to the Metro.

These ideas are just simple ways that WMATA could cut costs while improving service. There are probably other instances where these solutions could be applied throughout the region. From a rider’s point of view, headway improvements are too long in coming. In these lean times, these adjustments would be a valuable approach.